The present invention relates to devices for supplying a characteristic current flow which is particularly useful to supply charging current to electrical storage batteries, for example, charging lead-acid storage batteries.
Battery chargers of various types are commonly used and, include dynamoelectric devices which generally include rotating machines functioning through electro-magnetic phenomena associated with current carrying conductors passing through a magnetic field to provide a source of electricity for use in charging batteries as well as devices of the alternating current rectifier type. The dynamoelectric devices can be of the direct current type which generate polarized current which can be supplied directly to a battery or can provide an alternating current which is then rectified, as is known in the art, to provide a direct current fixed polarized source for battery charging.
Alternatively, charging devices are utilized using commercially available alternating current which is rectified and then supplied to the battery as direct current having fixed positive and negative polarity. Heretofore, it has been generally thought desirable to supply a generally stable, rectified, filtered voltage and current source for use in charging electric batteries and particularly for use in charging a lead-acid batteries. However U.S. Pat. No. 4,371,226 relates to a battery charging apparatus utilizing pulse width modulated constant current charging signals.
The means of conditioning and characterizing the charging current flow to the battery has been found to be important. One means for conditioning and characterizing the current flow is disclosed in copending patent application Ser. No. 639,090 which provides for improved operation performance by cyclical charging of a battery but does not provide for reverse current flow.
While the present invention is described in terms of charging lead-acid batteries it will be recognized that the methods and apparatus within the scope of the present invention are useful in charging other types of batteries and supplying current for other applications.
No prior art device is known to providing direct current electric charge to batteries and to supply a forward current flow to charge a battery where the current flow is periodically cycled and means are provided to allow reverse current flow of the battery charge current for a selected brief period of time in order to enhance characteristics of battery charging.